Ms. Cindy Ott-Jones Page 2

I. Proposed Action and Action Area The proposed action in this consultation includes a variety of management actions for exotic, invasive, threatened, and endangered on Federal land. The National Park Service (NPS) is proposing to enhance habitat for select federally listed species and manage exotic biota and trespass livestock in Big Bend National Park (BBNP). Located in Brewster County in west Texas along the Rio Grande / Río Bravo del Norte (Rio Grande), BBNP totals about 801,000 acres (ac) or 1,252 miles2 including inholdings. About 1,214 miles2 are Federal Land (Jameson 2010). Notable aspects of BBNP are: the broad diversity of and , its geologic history, the Chisos Mountains with panoramic views of exemplary Chihuahuan desert, and the Rio Grande with its scenic canyons and riparian areas. For a detailed description of BBNP, please see section 4.0 of the BA.

The NPS has prepared three documents for BBNP: Exotic Management Plan, Exotic Management Plan, and the Trespass Livestock Management Plan, collectively referred to as Exotic Species Management Plans. Additionally, the NPS has responsibilities for managing federally listed threatened and endangered species and their habitats in BBNP. The planned activities are detailed in the May 2015 BA and the Exotic Species Management Plan.

The NPS has provided its determinations that the proposed action may adversely affect the following federally threatened /endangered species:

Common Name Scientific Name Federal Status

bunched cory ramillosa Threatened

Echinocereus chisosensis var. Chisos hedgehog cactus Threatened chisoensis

Lloyd's mariposa cactus Echinomastus mariposensis Threatened

Big Bend Gambusia gaigei Endangered

black-capped vireo Vireo atricapilla Endangered

Threatened for western yellow-billed cuckoo Coccyzus americanus distinct population segment (DPS) Ms. Cindy Ott-Jones Page 3

The NPS determined that the proposed action will have “no effect” on a group of federally listed candidate, threatened, or endangered species known from BBNP. Additionally, the NPS determined that the proposed action may affect; but, is not likely to adversely affect: (1) the endangered Mexican long-nosed bat (Leptonycteris nivalis), (2) the endangered southwestern willow flycatcher (Empidonax traillii extimus), (3) the threatened Mexican spotted owl (Strix occidentalis lucida), (4) the non-essential experimental population of Rio Grande silvery minnow (Hybognathus amarus), and (5) the proposed critical habitat of the yellow-billed cuckoo as the effects of the proposed management actions are considered insignificant, discountable, or completely beneficial to the proposed critical habitat. Based on the description of the proposed action with conservation measures in the BA, the Service concurs with NPS’s determinations.

The term “action area” means all areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action. The BA describes the action area as generally the BBNP boundary; but, acknowledges that some management actions, e.g., generating turbidity in the Rio Grande /Río Bravo del Norte, would potentially have some effects outside of the BBNP boundary. The action area for this consultation includes all of the BBNP and nearby areas that may be affected by management actions (see Figure 7 of BA). We consider the action area to be BBNP and an area within 100 meters of the National Park boundary, which should capture the direct and indirect effects of the proposed action.

The proposed action has four management parts: exotic plants, exotic animals, trespass livestock, and habitat enhancement for select species, such as the Big Bend gambusia. The BA and individual management plans describe the activities planned to monitor and control impacts of exotic species and trespass livestock. Activities to reduce and control exotic plants and animals in BBNP will use an Integrated Pest Management (IPM) approach.

Management of Plants The highest management priority plant species in BBNP are: African buffelgrass (Cenchrus ciliaris), Lehmann’s lovegrass (Eragrostis lehmanniana), tamarisk (salt cedar) (Tamarix spp.), giant reed (Arundo donax), King Ranch (K-R) bluestem (Bothriochloa ischaemum var. songarica), Kleberg bluestem (Dichanthium annulatum), and Malta star-thistle (Centaurea melitensis). The treatment methods for exotic plants are detailed in the BA Tables 1 and 2 and include: (1) prescribed fire, (2) mechanical, (3) cultural, (4) chemical treatments, and (5) biological control agents.

The BBNP Fire Management Plan (NPS 2005) provides the framework for making fire-related decisions – responses and includes steps for initial action on ignitions pursuant to the goals and objectives of the plan.

Ms. Cindy Ott-Jones Page 4

Mechanical (manual) treatments involve digging with shovels or hoes, pulling /cutting by hand, chainsaws, and cutting of the cambium with a machete followed by application of gauze with herbicide.

Cultural control involves re-vegetating, irrigating, and/or fertilizing to establish healthy native ground cover, resistant to invasive plants.

Chemical treatments would include coordination with Regional and National IPM Coordinators and would comply with the NPS Director’s Order-77. The methods of herbicide application would depend on the target species and range from hand application with non-powered sprayers to battery- or gasoline-powered sprayers mounted in trailers, trucks, or boats, to aerial spraying (e.g., for larger stands of giant reed in the floodplain). A significant number of the proposed treatment areas for exotic plants are roadside and developed areas. A few of the roadside areas may be occupied by endangered cactus species. Management of emergent macrophytes in and near Big Bend gambusia habitat (ponds) may involve a combination of mechanical and chemical approaches.

Management of Animals other than Livestock The highest management priority animal species in BBNP parkwide are aoudads (Barbary sheep) (Ammotragus levia) and feral hogs (Sus scrofa). Depending on circumstances, localized parts of the BBNP may be controlled for the following species if their impacts reach a priority (action) threshold:

 nutria (Myocastor coypu)  red-eared slider (Trachemys elegans)  bullfrog (Rana catesbiana)  eastern green tree frog (Hyla cineria)  blue tilapia (Oreochromis aureus)  red imported fire ants (RIFA) (Solenopsis invicta)

A matrix of action thresholds, areas for treatment and treatment methods is presented in the BA’s Table 3. Figure 3 of the BA shows the initial priority management area for nutria, bullfrog, and green tree frog. The treatment methods for aoudads and feral hogs include shooting (aerial- and ground-based), trapping, fencing, and use of Judas (Lead) animals. Currently no treatment methods have been identified for blue tilapia and additional study is needed. To manage RIFA, surveys, study, and monitoring would typically precede control. Chemical approaches targeting RIFA would be used in a limited part of the Chisos Basin Campground and vicinity.

Trespass Livestock Management Trespass livestock involves burros, horses, and cattle that enter BBNP from adjacent properties in Mexico and U.S. The livestock damage the park’s natural resources and potentially spread Ms. Cindy Ott-Jones Page 5

diseases to other livestock, wildlife, and humans. Livestock may be: (1) returned to the owner (potentially with penalty), (2) roundup by mounted wranglers, (3) roundup assisted by helicopters, (4) subject to aerial capture and transport, (5) managed by fencing, (6) trapped, or (7) managed as Abandoned and Unclaimed Property pursuant to Federal regulations. Figure 4 in the BA shows the four management zones for trespass livestock in BBNP. Management of trespass livestock reduces the damage livestock pose to springs, water quality, soil conservation, and vegetation.

Management of Special Status Species The BBNP’s goals include improvement of habitats for southwestern willow flycatchers (Empidonax traillii extimus), yellow billed cuckoo (Coccyzus americanus), and black-capped vireos (Vireo atricapilla). The primary activity planned for aquatic species in this category is to ensure the habitat of the Big Bend gambusia is not adversely reduced by an overabundance of native cattails (Typha spp.), native reeds (Phragmites spp.), and non-native giant reed (Arundo donax). Physical – mechanical removal (e.g., with machetes) of cattails may occur in and near aquatic habitat occupied by Big Bend gambusia. Additionally, careful application of the herbicide imazapyr may be used to control these emergent macrophytes. Imazapyr (Arsenal®) has a low potential toxicity and is not known to be toxic at environmentally relevant concentrations to , livestock, or humans. However, any herbicidal treatments in Big Bend gambusia habitat will be done incrementally (treating less than a third of a pond annually) to avoid oxygen depletion from decomposing plant material. The removal of emergent vegetation in Pond No. 1 and the Hubbs Refuge is expected to double or triple the amount of suitable Big Bend gambusia habitat by restoring more open water.

Conservation Measures Section 3.1.6 of the BA describes the varied ways in which the management plans: (1) avoid, reduce, or eliminate adverse effects to listed species and (2) benefit federally listed species and their habitats. These include: avoiding and reducing the adverse effects of vehicles; minimizing ground disturbance; minimizing herbicide application rates, wherever possible; using lead-free ammunition; safety training for staff; outreach and education for visitors to reduce human impacts, treating small areas and monitoring water quality before and after work in Big Bend gambusia habitats to ensure supportive conditions; and in general maintaining the native communities across the BBNP landscape by detecting and controlling exotic plant species.

Ms. Cindy Ott-Jones Page 6

. Status of the Species

BUNCHED CORY CACTUS Description and Life History

The bunched cory cactus was federally listed as threatened effective December 6, 1979 (44 FR 64247). Critical habitat was not designated. The stems are dark grayish green and solitary or rarely with a few branches (Service 1989a). The flower petals are about 2 inches (in) long, pink but lighter near the base (NPS 2015).

The rounded fruits are pale to dark green (NPS 2015) and form in October through December and are about 1 – 2.5 centimeter (cm) long (Heil et al. 1985). Seeds are about 1.5 millimeter (mm) long and reddish-brown. Bunched cory cactus grows in desert scrubland (Brown and Lowe 1980) and among rocky, well-drained limestone outcrops (Service 1989a). Texas Parks and Wildlife Department (2015) describes its habitat as: “rocky slopes, ledges, and flats in the Chihuahuan Desert, Bunched Cory Cactus most frequently on exposures of Santa Elena or Buda limestones or the Boquillas Formation between 400 – 1,070 meters (m) (1,300 - 3,500 feet (ft) in elevation; flowering August-November, perhaps as early as April in response to rainfall.”

Populations, Status, and Distribution The known range for the bunched cory cactus includes Brewster and Terrell Counties, Texas and Coahuila, Mexico. Rangewide, the number of individuals is estimated at 5,000 to 10,000. Within BBNP, the number of individuals is estimated at 800 to 900. Its distribution is inferred to be similar to the time of listing, on BBNP, State, private, and Mexican lands.

Ms. Cindy Ott-Jones Page 7

CHISOS HEDGEHOG CACTUS Description and Life History The Chisos Mountains hedgehog cactus was federally listed as endangered in 1988 (53 FR 38453). The common name is somewhat misleading as it occurs on alluvial flats rather than in mountains. Single, cylindrical stems are green to blue-green in the spring and summer, which turn reddish- maroon in the winter (Service 1993). Typically, this species grows to about 25 cm (10 in) high. Spines are relatively sparse. The flower petals are deep red at the base and have white tips (Evans 1986). This species flowers from March to early June and fruits from May to August (Heil and Anderson 1982b). The conspicuous fruits are fleshy and green-red (Heil and Anderson 1982a). Little else is known about the phenology or reproductive biology. A Chisos (Mountains) Hedgehog has not been identified (Heil and Anderson Cactus 1982a) and seed dispersal mechanisms are unknown.

Populations, Status, and Distribution The known range of this species is restricted to BBNP. Heil and Anderson (1982b) and Heil et al. (1988) stated that the species had not been found in Mexico. However, Taylor (1985) and Anderson (2001) describe the distribution of the cactus as west Texas and south into Coahuila and Durango, Mexico. Texas Plant Conservation Conference (2003) and Jackie Poole (Texas Parks and Wildlife Department, pers. comm. 2004) state that specimens in Mexico are of the variety fobeanus, not chisoensis.

This species is threatened by infestation of the exotic buffelgrass, particularly along arroyos. Guertin and Halvorson (2004) found buffelgrass growing in proximity to the cactus, particularly on the north side of Route 12. While this species is normally not threatened by fire due to the lack of flammable fuel load in its typical habitat, buffelgrass is flammable, hence there is concern that it could carry a fire and threaten individual cacti nearby. Chisos Mountains hedgehog cactus is generally found growing near or under creosote bush (Larrea tridentate), lecheguilla (lechuquilla) (Agave lecheguilla), or among dog cholla (Opuntia schottii) (Kathy Rice, Desert Botanical Garden, pers. comm. 2005, Service 1993).

The recovery plan (Service 1993) cites illegal collecting as the most immediate threat to the Chisos Mountains hedgehog cactus. There is evidence that poaching of rare cactus species in BBNP is ongoing (Betty Alex 2005 and Mike Fleming 1993, Big Bend National Park, pers. comm.). Rees (1988) also speculates that habitat degradation from former grazing, climate change, or other unknown factors may be limiting seed establishment. The decline of grasses Ms. Cindy Ott-Jones Page 8

due to fire suppression and overgrazing may have resulted in the cactus becoming associated with nurse plants (Heil and Anderson 1982b, Service 1988). In their overview of threats to cacti, Goettsch et al. (2015) identified collection for human use (e.g., ornamental horticulture) as a predominant threat. Delisting criteria in the recovery plan state that 50 distinct populations of at least 100 reproductive individuals are established within a minimum area of 4 - 8 hectares (10 - 20 ac). These populations must demonstrate stability and reproductive success over a period of at least 10 years (Service 1993).

The BBNP has identified about 23,974 ac in the southeast part of the park as the area of occurrence for the Chisos Mountains hedgehog cactus (Figure 17 of the BA). There are about 24.2 miles of roads and trails in this area.

Ms. Cindy Ott-Jones Page 9

LLOYD’S MARIPOSA CACTUS Description and Life History Lloyd’s mariposa cactus was listed as a federally threatened species effective December 6, 1979, (44 FR 64247 – 64250) without critical habitat. It is a small cactus associated with the Chihuahuan Desert scrublands. It has cylindrical stems up to 4 in. Flowers petals are white and pink, up to 1.2 in and fruits are yellow-green, up to 0.4 in (Weniger 1970). The recovery plan describes the length and shape of the spines. This species is found on rocky alkaline soils of limestone gravels on BBNP’s hills and among the lower mesa slopes between 2,500 and 3,500 ft elevation.

Populations, Status, and Distribution Historically, Lloyd’s mariposa cactus occurs in more

than 10 sites in Brewster County and in three sites in Lloyd's Mariposa Cactus Coahuila, Mexico, two of which are near Cuatro Ciénegas (Service 1989b). The number of individuals by site is not available and densities have been described as scattered to occasionally dense. The NPS is monitoring this species within BBNP, but sparse information is available regarding populations outside BBNP.

Ms. Cindy Ott-Jones Page 10

BIG BEND GAMBUSIA Description and Life History Big Bend gambusia is a small livebearing fish in the family that is strictly endemic to BBNP. Big Bend gambusia was described by Carl Hubbs (1929) noting it was small relative to its congeners with males about 17 to 23 mm long and females slightly larger.

Its diet includes aquatic invertebrates such as ostracods, copepods, amphipods, and larval insects. Gambusia are eaten by predatory , snakes, and birds. The type locality was a marshy cattail slough fed by warm springs. Photographs in 2003, 2008, 2010, and 2014 have documented the change in the extent of open water in Pond No. 1 (and the Hubbs Refuge since its creation) with cattails expanding to Big Bend gambusia. cover more of the pond. Meffe and Snelson (1989) reviewed the ecology of poeciliid fishes, stating poeciliids often occupy “fringe habitats” in harsh areas. Big Bend gambusia fits this description as it is a springhead endemic of the Chihuahuan Desert and relies entirely on shallow open water habitat in ponds supported by small discharge warm springs. Hubbs and Springer (1957) noted that the “clear warm-water springs are so different” than nearby turbid - muddy aquatic habitats (e.g., Rio Grande) that Big Bend gambusia would only be present outside the springheads as strays.

Populations, Status, and Distribution Big Bend gambusia are found only in a series of small ponds and waterways in the Rio Grande Village area of BBNP. There are four ponds in the area: Spring 1 Refuge Pond (also known as Pond 1), Hubbs Refuge Pond (in honor of Clark Hubbs, also known as Spring 4 Refuge Pond), Spring 4 Outflow Pond (also known as Spring 4 Pond), and Beaver Pond. The primary populations are associated with a pond fed by warm-spring water designated as Pond 1 and the Hubbs Refuge Pond. Two ponds downstream of the Hubbs Refuge Pond, Spring 4 Outflow Pond and Beaver Pond, may have small numbers of Big Bend gambusia on occasion. However, in September 2008, the Rio Grande flood covered the Outflow and Beaver Ponds negatively affecting the potential of these ponds to support Big Bend gambusia. Robert Edwards, University of Texas Rio Grande Valley, has been regularly monitoring the Big Bend gambusia and the number of individuals caught per trap since 2011 have been relatively stable.

Pond No. 1 and the Hubbs Refuge are each about 60 ft long and 30 ft wide or 1,800 ft2 (0.041 ac or about 167 m2). No total population estimates are available for either Pond No. 1 or the Hubbs Refuge but regular (typically annual) minnow trap surveys (6 traps per pond) have averaged about 51 Big Bend gambusia per trap for Pond No. 1 and 42 Big Bend gambusia per trap for Ms. Cindy Ott-Jones Page 11

Hubbs Refuge (Edwards, in litt., 2014). On average, Edwards has caught about 309 Big Bend gambusia in Pond No. 1 and 250 Big Bend gambusia in the Hubbs Refuge. Thus, conservatively assuming his average capture with six traps represents about 25 percent of the pond population, the populations of Pond No. 1 and Hubbs Refuge each exceed 1,000.

Ms. Cindy Ott-Jones Page 12

BLACK-CAPPED VIREO Description and Life History The black-capped vireo (BCVI) was federally listed as endangered on October 6, 1987 (52 FR 37420). No critical habitat has been designated for this species.

The BCVI is an insectivorous migratory songbird about 4.5 in long (Service 1991). Male adult BCVI are mostly olive-green above and white below (Grzybowski 1995). Adult BCVI have a black and/or gray cap and reddish eye distinguishing adults from other species. Although BCVI habitat throughout Texas is quite variable with respect to plant species, soils, and rainfall, habitat types generally have a similar overall appearance. Black-capped Vireo, Big Bend National Park, 2015 The BCVI typically inhabits Photo courtesy of Eric M. Wood shrublands and open woodlands California State University Los Angeles with a distinctive patchy structure. The vegetation generally extends from the ground to about six feet above ground and covers about 30 to 60 percent of the total area. In the Edwards Plateau, common plants in BCVI habitat include Texas oak (Quercus texana), shin oak (Q. sinuata), live oak (Q. virginiana and Q. fusiformis), mountain laurel (Sophora secundiflora), evergreen sumac (Rhus virens), redbud (Cercis canadensis), Texas persimmon (Diospyros texana), mesquite (Prosopis glandulosa), and agarita (Mahonia trifoliata). In the Edwards Plateau, suitable habitat for the BCVI often includes early successional scrub/shrub created by fire or woodland clearing. Black-capped vireos are opportunistic foragers; however, they prefer insect larvae and seeds (Grzybowski 1995).

Male BCVI arrive in Texas in mid-March to mid-April and begin to establish breeding territories, which they defend against other males by singing within their territories (Service 2007). Females arrive a few days later, but are more difficult to detect in the dense brushy habitat. Nesting occurs in April and three to four eggs are generally incubated for 14 to 17 days. There may be a second nesting attempt. Nestlings fledge 10 to 12 days after hatching (May to early June). In mid-July, BCVI start their migration south, beginning with females and young and followed by adult males (Campbell 2003, Graber 1957, Oberholser 1974). Typically, BCVI are gone from Texas by mid-September.

Ms. Cindy Ott-Jones Page 13

Populations, Status, and Distribution Black-capped vireos breed from Oklahoma south through central Texas to the Edwards Plateau, then south and west to central Coahuila, Nuevo León, and southwestern Tamaulipas, Mexico, and they winter on the Pacific slope of Mexico. Populations have been extirpated in Kansas and have been reduced in Oklahoma, suggesting habitat loss and parasitism may be particularly prevalent in that part of the species’ range (Grzybowski 1995, Wilkins et al. 2006). The current section 7 consultation range of the BCVI includes 67 counties in Texas and 8 counties in Oklahoma. Records indicate that BCVI are currently known from only 51 counties in Texas and 4 counties in Oklahoma.

Wilkins et al. (2006) estimated that in 2005, the known United States population of BCVI was about 6,000 males, an apparent increase above 1987 estimates. It is unknown whether estimated population numbers have increased due to: (1) increased survey efforts, (2) differences in models for estimating population size, (3) increased habitat due to habitat management efforts, or (4) some combination of these. About 75 percent of the population is known from three locations, two in Texas including the Kerr Wildlife Management Area and Fort Hood, and one in Oklahoma shared between the Wichita Mountains Wildlife Refuge and adjacent U.S. Army Installation Fort Sill (Wilkins et al. 2006). Using records since 2006, there are 31 BCVI populations with more than 30 individuals, 10 of which contain more than 100 individuals. Within Texas many efforts are underway to assist landowners in determining the status of BCVI on their property and to educate landowners on the implementation of beneficial management strategies . Fully understanding the current distribution of the BCVI in Texas largely depends on the data collected through these efforts.

Threats to the BCVI include habitat loss, fragmentation, and degradation due to development, vegetational succession, poor grazing practices, and brown-headed cowbird parasitism. A complete summary of the threats to the species can be found in in the Service’s 5-year review (Service 2007). The protection of existing viable populations is critical to the survival and recovery of this species. Based on the BCVI Recovery Plan (Service 1991), protection and management of occupied habitat, and the minimization of further degradation, development, or modification of unoccupied habitat are necessary to provide for the survival of the species. Habitat protection must include elements of both breeding and non-breeding habitat (i.e., associated uplands, nearby riparian woodlands, and migration corridors). Efforts to create new, and protect existing, habitat will enhance the BCVI’s ability to expand in distribution and numbers.

Ms. Cindy Ott-Jones Page 14

YELLOW-BILLED CUCKOO Description and Life History The western distinct population segment of the yellow-billed cuckoo was listed as threatened effective November 3, 2014 (79 FR 59992). It is a member of the avian family Cuculidae and is a neotropical migrant that breeds in North America and winters in South America via Central America. The yellow-billed cuckoo is described as a slender long-tailed medium-sized bird about 12 in long (Hughes 2015). Adults have a stout and slightly down-curved bill. Western yellow-billed cuckoos prefer desert riparian woodlands of sufficient size with cottonwoods (Populus fremontii), willows (Salix spp.), alders (Alnus sp.), walnut (Juglans sp.), box elder (Acer negundo), and mesquite

(Prosopis spp). This cuckoo has a clutch size Yellow-billed Cuckoo of two to three eggs and is a facultative brood parasite, it will occasionally lay eggs in nests of Photo by Mark Dettling, USFWS other yellow-billed cuckoos or of other bird species. Hughes (2015) states that most western yellow-billed cuckoos probably have a single brood reared per season and that they feed primarily on large insects. Raptors may prey on adults and eggs and nestlings may be taken by avian predators, mammals, or snakes (Potter 1980, Hughes 2015).

Populations, Status, and Distribution The distinct population segment (DPS) listed as threatened, in the United States is the area west of the continental divide, south through Montana, Wyoming, Colorado, and along the watershed divide between the upper and middle Rio Grande and Pecos Rivers in New Mexico and Texas, south to the Big Bend region, and extending to the States of the west coast (e.g., California). Dettling et al. (2015) noted a decline in their study area in central California, but were unable to determine contributing factors. In Mexico, the DPS includes the States of Chihuahua, Sonora, and Sinaloa (see Figure 2, 79 FR 59999 and Figure 1 - Breeding Distribution for the entire species in Hughes 2015).

Ms. Cindy Ott-Jones Page 15

III. Environmental Baseline

The respective ranges of the Chisos hedgehog cactus and Big Bend gambusia are contained within the action area and the status of these two species described above in Section II is their environmental baseline. For listed plants, the factors affecting these species in BBNP are similar. All are subject to: (1) damage by vehicles that stray from the park’s roads, (2) human collection despite prohibitions, and (3) trampling by trespass livestock.

BUNCHED CORY CACTUS The population of bunched cory cactus in BBNP is estimated at about 800 to 900 plants, representing about 8 - 18 percent of the species rangewide (Texas and Coahuila). The BA notes that this species has an uneven density and distribution and identified an area about 1,118 ac as the general distribution of bunched cory cactus within BBNP. Within this area, there are about 1.4 miles of roads and trails. Figure 17 in the BA shows the general distribution in BBNP of bunched cory cactus as well as Lloyd’s mariposa cactus and Chisos Mountains hedgehog cactus. In BBNP, bunched cory cactus occurs on bluffs above the Rio Grande, the tops of small hills, or on rocky flats below the hills. The BBNP is monitoring all known locations.

LLOYD’S MARIPOSA CACTUS The distribution of Lloyd’s mariposa cactus in BBNP is patchy. The BA presents two areas that represent the general parts of BBNP where Lloyd’s mariposa cactus occurs. The smaller area in the western part of the park is about 955 ac and does not appear to have any roads or trails. The larger area in northeastern part of the park is about 51,142 ac and has about 32.7 miles of roads and trails. Presently, there are no indications that the distribution within BBNP has changed. BBNP is monitoring all known locations.

BLACK-CAPPED VIREO Annual surveys of black-capped vireos (BCVI) in BBNP began in 1988. Figure 1 (below) and Figure 11 of the BA show the areas searched and locations of BCVI primarily among the brushy drainages. Pomara and Wood (2015) found 36 male BCVI and 1 female BCVI, which represents an increase from the 2014 surveys (Pomara 2014).

Ms. Cindy Ott-Jones Page 16

Figure 1. Black-capped vireo survey areas in Big Bend National Park.

YELLOW-BILLED CUCKOO Section 7.1.2 of the BA reviews the yellow-billed cuckoo sightings in BBNP and Figure 9 of the BA shows the location of the sightings and the distinct population segment boundary that roughly bisects BBNP. Based on the presence of suitable habitat, it appears that riparian sections of the Rio Grande and parts of the lower Terlingua Creek riparian area are the most likely parts of BBNP to be occupied by the yellow-billed cuckoo. Occasional sighting of yellow-billed cuckoos have been reported in and near the Chisos Mountains (eBird 2015), overlapping with areas surveyed for black-capped vireo.

Ms. Cindy Ott-Jones Page 17

IV. Effects of the Action Cactus Species Bunched Cory Cactus, Lloyd’s Mariposa Cactus, and Chisos Mountains Hedgehog Cactus The management of exotic plants, exotic animals, and trespass livestock, in general, will have benefits for the listed threatened cacti by reducing: (1) the degradation of habitat (e.g., competition with buffelgrass and K-R bluestem) and (2) trampling of cactus by livestock that roam the drier upland areas east of the Chisos Mountains, where all three cactus species occur. Section 8.1.1 of the BA discusses the treatment methods specific to herbaceous and woody exotic species. The listed cactus species mostly occur in parts of BBNP that is not visited regularly and there are few campgrounds and hiking trails in areas occupied by bunched cory cactus, Lloyd’s mariposa cactus, and Chisos Mountains hedgehog cactus. A few populations of listed cactus species occur near roads and interpretive areas. While some individual cacti near roads may be damaged by road maintenance and treatment of exotic grasses adjacent to the road, the vast majority of the three listed cactus species occur away from the roads. Thus, most of the listed cacti in BBNP will not be affected by exotic plant management treatments, including prescribed fire. Big Bend Gambusia The main effect of treatments to enhance Big Bend gambusia habitat will be the temporary disturbance from removing cattails in the target ponds. Management of the water distribution system, which includes pumping, will entail repairs and upgrades. Management of ponds supporting Big Bend gambusia will involve: (1) treatment and removal of overgrown emergent vegetation stands (cattails, reeds, and giant reed) that reduce open water habitat needed by Big Bend gambusia; (2) removal of beavers and nutria that degrade gambusia habitat, increasing turbidity, and reducing water quality; and (3) management of bullfrogs and eastern green treefrogs, which may compete with gambusia for aquatic invertebrates. The proposed activities that will reduce the overgrown emergent vegetation will temporarily affect part of the gambusia ponds when the plants are either treated with an herbicide (safe for fish and aquatic invertebrates) or mechanically removed (e.g., digging with shovels). The proposed treatment of emergent aquatic vegetation in Big Bend gambusia ponds is described as minor. It will involve monitoring before, during, and after the treatment. Importantly, less than a third of the pond would be treated in any single year to help ensure that any decaying vegetation in the pond does not have an overall impact on water quality e.g., dissolved oxygen. Incidental temporary turbidity will occur when BBNP staff and cooperators enter the ponds for treatment, but the overall amount of gambusia habitat should increase post-treatment. A diverse variety of conservation measures to be implemented are detailed in section 3.1.6.2 of the BA.

Black-Capped Vireo Black-capped vireos (BCVI) arrive in BBNP in March and Fall migration occurs mostly in August and September (Grzybowski 1995). About 6,300 ac of potential BCVI habitat has been surveyed in BBNP since 2009. The brushy draws used by BCVI in BBNP presently do not have Ms. Cindy Ott-Jones Page 18

exotic plant species present at levels that warrant management. If plant management is needed in the future, it would be done outside the breeding season and woody species used by BCVI would be conserved. The BCVI may be disturbed by treatments of exotic grasses if timing of treatments necessitated work during the breeding season. The use of helicopters to control feral hogs and aoudads is not likely to overlap with BCVI in BBNP as hogs and aoudads tend to be found in areas distant from BCVI habitat, and if found, feral hogs and aoudads will be treated outside the BCVI breeding season.

Yellow-Billed Cuckoo The main activity that may affect the western distinct population segment of the yellow-billed cuckoo is the removal of giant reed and tamarisk along the Rio Grande. The seasonal occurrence of yellow-billed cuckoo, western distinct population segment in BBNP is centered along the riparian corridor of the Rio Grande (upstream of Mariscal Canyon) and Terlingua Creek. Reports from the citizen science dataset for bird observations, eBird (2015), include sightings in the Chisos Mountain Basins and Santa Elena Canyon. The 2015 surveys in BBNP that have found yellow-billed cuckoos are associated with larger mature mesquite with accessible horizontal branches (Pomara and Wood 2015). Giant reed in BBNP occurs along the Rio Grande, but is more prevalent in the reaches downstream of Mariscal Canyon where the floodplain is broader. Several large patches of giant reed occur upstream of Mariscal Canyon. Some of these upstream patches may be subject to treatment, with the prescribed conservation measures to help protect yellow-billed cuckoo breeding habitat.

No more than 20 river-miles of giant reed/tamarisk will be removed in a given year. While it is possible that the cuckoo may use the giant reed and/or tamarisk for foraging, there appears to be adequate untreated foraging habitat nearby. The treatment of giant reed in BBNP involves prescribed burns and spraying of Imazapyr. BBNP has indicated that giant reed does not constitute cuckoo breeding habitat. Giant reed may be treated in areas adjacent to cuckoo habitat but only outside the cuckoo breeding season. Additionally, fire breaks will be used to prevent impacts to mature mesquite. Where fire is used to control giant reed, conservation measures include breaks to help prevent inadvertently harming mature mesquite used by the yellow-billed cuckoo. Helicopter use for feral hog and aoudad control may on occasion disturb or flush individual cuckoos. However, there is no apparent association of feral hogs and aoudads with habitats favored by yellow-billed cuckoos. No vegetation management efforts (e.g., giant reed control) are planned in breeding habitat. There may also be smaller scale (less than 20 ac patches) management of tamarisks (also Kleberg bluestem and K-R bluestem) in the Terlingua Creek riparian corridor. However the tamarisk is not thought to have the structural features preferred by cuckoos for nesting.

V. Cumulative Effects

Ms. Cindy Ott-Jones Page 19

Cumulative effects including the effects of future State, local, or private actions that are reasonably certain to occur in the action area are considered in this biological opinion. Future Federal actions that are unrelated to the proposed action are not considered in this section because they require separate consultation pursuant to section 7 of the Act.

As a result of being a National Park, virtually no cumulative effects are expected to occur in the action area. We are unaware of any non-Federal actions in BBNP that would be expected to affect the listed species in this consultation.

VI. Conclusion

After review of the current status of the bunched cory cactus, Lloyd’s mariposa cactus, Chisos Mountains hedgehog cactus, Big Bend gambusia, yellow-billed cuckoo, and black-capped vireo, the environmental baseline for the action area, and the cumulative effects, it is the Service’s biological opinion that the Big Bend National Parks management plan for threatened species, endangered species, exotic species, and trespass livestock is not likely to jeopardize the continued existence of any of the species in this consultation. This conclusion is based on implementation of conservation measures described in the biological assessment and individual management plans.

INCIDENTAL TAKE STATEMENT Section 9 of the Act and Federal regulation pursuant to section 4(d) of the Act prohibit the take of endangered and threatened species, respectively, without special exemption. Take is defined as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or to attempt to engage in any such conduct. Harm is further defined by the Service to include significant habitat modification or degradation that results in death or injury to listed species by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering. Harass is defined by the Service as intentional or negligent actions that create the likelihood of injury to listed species to such an extent as to significantly disrupt normal behavior patterns which include, but are not limited to, breeding, feeding or sheltering. Incidental take is defined as take that is incidental to, and not the purpose of, the carrying out of an otherwise lawful activity. Under the terms of section 7(b)(4) and section 7(o)(2), taking that is incidental to and not intended as part of the agency action is not considered to be prohibited taking under the Act provided that such taking is in compliance with the terms and conditions of this incidental take statement.

The measures described below are nondiscretionary and must be implemented by the National Park Service so that they become binding conditions of any authorization issued to implement an activity covered by this biological opinion, as appropriate, in order for the exemption in section 7(o)(2) to apply. The National Park Service has a continuing duty to regulate the activity Ms. Cindy Ott-Jones Page 20 covered by this incidental take statement. If the National Park Service: (1) fails to adhere to the terms and conditions of the incidental take statement through enforceable terms that are added to the authorizations, and/or (2) fails to retain oversight to ensure compliance with these terms and conditions, the protective coverage of section 7(o)(2) may lapse. To monitor the impact of incidental take, the National Park Service must report the progress of the action and its impact on the species to the Austin Ecological Services Field Office as specified in the incidental take statement. [50 CFR 402.14(i)(3)].

Amount or Extent of Take Anticipated

Big Bend Gambusia The Service anticipates that no more than 56 meter2 of Big Bend gambusia habitat will be disturbed per pond per year of treatment for overabundant emergent aquatic vegetation (primarily cattails). The aquatic habitat that is most likely to have Big Bend gambusia are Pond 1 and the Hubbs Refuge Pond. The National Park Service may also treat other aquatic habitat downstream of these two ponds for giant reed, phragmites, and cattails, but significantly fewer Big Bend gambusia are anticipated to be affected by vegetation control in the lower ponds due to lower densities and less suitable habitat. The removal of cattails in Pond 1 and the Hubbs Refuge Pond is anticipated to harass about 300 Big Bend gambusia on an annual basis (for years with treatment of emergent aquatic vegetation), but not result in any mortality of Big Bend gambusia.

The Spring 4 Outflow Pond and the Beaver Pond (Lower Ponds) may be treated for overabundant emergent aquatic vegetation. These lower ponds are more distant from the warm springs and are estimated to have low densities of Big Bend gambusia (relative to Pond 1 and the Hubbs Refuge Pond), if any occur there. The Service anticipates that less than 100 Big Bend gambusia will be disturbed but not killed by treatments to remove cattail, giant reed, and phragmites from these lower two ponds (Spring 4 Outflow Pond and Beaver Pond).

Black-Capped Vireo The Service anticipates that the proposed exotic plant management efforts will not reduce the approximate 6,300 ac of brush draw habitat potentially used by black-capped vireos. Helicopter use for exotic animal management efforts may rarely disturb BCVI during the months of March through September.

Yellow-Billed Cuckoo The Service anticipates that 20 river-miles of riparian vegetation of the Rio Grande along the left bank looking downstream will be treated on annual basis for giant reed and/or tamarisk. The control of giant reed and tamarisk along Terlingua Creek and the Rio Grande upstream of Mariscal Canyon may disturb and harass individuals of the western distinct population segment Ms. Cindy Ott-Jones Page 21

of the yellow-billed cuckoo that may be foraging among treated exotic vegetation. The Service anticipates that no yellow-billed cuckoos will be killed as a result of the exotic plant control planned by BBNP, but that an unknown limited number of yellow-billed cuckoos will be harassed by vegetation management activities.

Effect of the take

In the accompanying biological opinion, the Service has determined that this level of anticipated take is not likely to result in jeopardy to the bunched cory cactus, Lloyd’s mariposa cactus, Chisos Mountains hedgehog cactus, Big Bend gambusia, yellow-billed cuckoo, and black- capped vireo. The Service has concurred with the National Park Service’s determination that the proposed action is not likely to adversely affect the proposed critical habitat of the western distinct population segment of the yellow-billed cuckoo.

REASONABLE AND PRUDENT MEASURES

The Service believes the following reasonable and prudent measures (RPM) are necessary and appropriate to minimize incidental take of the species in this consultation:

RPM 1. Minimize harm and harassment of Big Bend gambusia by minimizing habitat disturbance and the duration of disturbance.

RPM 2. Minimize harm and harassment of black-capped vireo and western distinct population segment of yellow-billed cuckoo by avoiding when possible species management activities near occupied habitat during the breeding season and ensuring conservation of woody plant species used by these species throughout the duration of this consultation.

Terms and Conditions In order to be exempt from the prohibitions of section 9 of the Act, the National Park Service must comply with the following terms and conditions, which implement the reasonable and prudent measures described above and outline the required reporting/monitoring requirements. These terms and conditions are non-discretionary.

Term and Condition 1 for RPM 1. The National Park Service will follow the conservation measures described in the biological assessment and exotic species management plans and ensure that aquatic habitat conditions for Big Bend gambusia in Pond No. 1 and the Hubbs Refuge are supportive. The National Park Service, in cooperation with members of the Rio Grande Fishes Recovery Team, will monitor Ms. Cindy Ott-Jones Page 22

and estimate local abundance of the Big Bend gambusia populations in known occupied habitats annually. Reports for previous calendar year should be provided to the Service annually by February 28.

Term and Condition 2 for RPM 2. The National Park Service will follow the conservation measures described in the biological assessment, exotic species management plan, and trespass livestock plan and: (a) continue to assess and monitor habitats used by black-capped vireos and yellow-billed cuckoos in the western distinct population segment; (b) update maps and GIS coverages for vireo and cuckoo habitats regularly, (c) ensure that management of exotic species and trespass livestock avoids habitats occupied by black-capped vireos and yellow-billed cuckoo to the maximum practicable extent, and (d) when habitat for these species cannot be avoided during the breeding season, the National Park Service will minimize the amount of habitat that may be adversely affected by proposed activities as well minimizing the duration of the disturbance.

Term and Condition 3 for RPM 2. The monitoring of black-capped vireos in BBNP should endeavor to: (a) quantify nesting success and productivity and (b) track and report on the local abundance of cowbird species (Molothrus spp.) in BBNP and specifically in and near black-capped vireo habitat

Term and Condition 4 for RPM 1 and 2. The National Park Service will summarize activities covered by this consultation on a calendar year basis and report on the areas treated for exotic plants, summarize management efforts for exotic animals and trespass livestock and describe the current status of species covered by this consultation in Big Bend National Park. The report summarizing the previous year should be provided to the Service annually by February 28.

Conservation Recommendations

Section 7(a)(l) of the Act directs Federal agencies to utilize their authorities to further the purposes of the Act by carrying out conservation programs for the benefit of endangered and threatened species. Conservation recommendations (CR) are discretionary agency activities to minimize or avoid adverse effects of a proposed action on listed species or critical habitat, to help implement recovery plans, or to develop information.

CR 1. The National Park Service is encouraged to continue its assistance and cooperation with conservation efforts in Coahuila and Brewster County outside BBNP including monitoring of threatened and endangered species: bunched cory cactus, Lloyd’s mariposa cactus, black-capped vireo, and yellow-billed cuckoos.

Ms. Cindy Ott-Jones Page 24

Literature Cited

Anderson, E.F. 2001. The Cactus family. Timber Press. Portland OR.

Brown, D.E. and C.H Lowe. 1980. Map, biotic communities of the Southwest. Rocky Mountain Forest and Range Experiment Station. U.S. Department of Agriculture, Forest Service, Fort Collins, CO.

Campbell, L. 2003. Black-capped vireo. In: Endangered and threatened animals of Texas, their life history and management. Texas Parks and Wildlife Department, Austin, TX.

Cutak, L. 1942. Coryphantha ramillosa, a new species from the Big Bend Region of Texas. Cactus and Succulent Journal 14:164.

Dettling, M.D., N.E. Seavy, C.A. Howell, and T. Gardali. 2015. Current status of western yellow-billed cuckoo along the Sacramento and Feather rivers, California. PLOS ONE 10(4):e0125198. doi:10.1371/journal.pone.0125198. eBird. 2015. An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. Available: http:///www.ebird.org. (Accessed: October 8, 2015).

Echelle, A.A., D.M. Wildrick, and A.F. Echelle. 1989. Allozyme studies of genetic variation in Poeciliid fishes. Chapter 12 in Ecology and Evolution of Livebearing Fishes (Poeciliidae), edited by G.K. Meffe and F.F. Snelson, Jr. Prentice Hall, Englewood Cliffs, NJ.

Edwards, R.J. 2014. Endangered species permit report, University of Texas Rio Grande Valley. to U.S. Fish and Wildlife Service.

Evans, D.B. 1986. Survey of Chisos pitaya ( reichenbachii var chisosensis). National Park Service, Big Bend National Park, Texas. 18 pp.

Goettsch, B., C Hilton-Taylor, G. Cruz-Piñón, J.P. Duffy, A. Frances, H.M. Hernández, R. Inger, C. Pollock, J. Schipper, M. Superina, N.P. Taylor, M. Tognelli, A.M. Abba, S. Arias, H.J. Arreola-Nava, M.A. Baker, R.T. Bárcenas, D. Barrios, P. Braun, C.A. Butterworth, A. Búrquez, F. Caceres, M. Chazaro-Basañez, R. Corral-Díaz, M. Perea, P.H. Demaio, W.A. Duarte de Barros, R. Durán, L.F. Yancas, R.S. Felger, B. Fitz-Maurice , W.A. Fitz- Maurice, G. Gann, C. Gómez-Hinostrosa, L.R. Gonzales-Torres, M.P. Griffith, P.C. Guerrero, B. Hammel, K.D. Heil, J. Hernández-Oria, M. Hoffmann, M.I. Ishihara, R. Kiesling, J. Larocca, J. León-de la Luz, C.R. Loaiza S., M. Lowry, M.C. Machado, L.C. Ms. Cindy Ott-Jones Page 25

Majure, J.G. Martínez Ávalos, C. Martorell, J. Maschinski, E. Méndez, R.A. Mittermeier, J.M. Nassar, V. Negrón-Ortiz, L.J. Oakley, P. Ortega-Baes, A.B. Pin Ferreira, D.J. Pinkava, J.M. Porter, R. Puente-Martinez, J. Roque Gamarra, P. Saldivia Pérez, E. Sánchez Martínez, M. Smith, J.M. Sotomayor M. del C., S.N. Stuart, J.L. Tapia Muñoz, T. Terrazas, M. Terry, M. Trevisson, T. Valverde, T.R. Van Devender, M.E. Véliz-Pérez, H.E. Walter, S.A. Wyatt, D. Zappi, J.A. Zavala-Hurtado, and K.J. Gaston. 2015. High proportion of cactus species threatened with extinction. Nature Plants. Article No. 15142. doi:10.1038/NPLANTS.2015.142.

Graber, J. 1957. A bioecological study of the black-capped vireo (Vireo atricapillus). Ph.D. dissertation, University of Oklahoma, Norman, OK.

Gryzbowski, J.A. 1995. Black-capped vireo (Vireo atricapilla). The birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: htt://bna,birds.cornell.edu/bna/species/181. doi:10.2173/bna.181.

Guertin, P. and W. Halvorson. 2004. Report on field mapping of Pennisetum ciliare in Big Bend National Park, 2003 and 2004. For National Park Service.

Heil, K.D. and E.F. Anderson. 1982a. Status Report on Echinocereus chisoensis. U.S. Fish and Wildlife Service, Albuquerque, NM. 19 pp.

Heil, K.D. and E.F. Anderson. 1982b. Determination that Echinocereus chisoensis is threatened. U.S. Fish and Wildlife Service, Albuquerque, NM. 13 pp.

Heil, K.D. S. Brack, and J.M. Porter. 1988. The rare and sensitive cacti of Big Bend National Park. National Park Service, Santa Fe, NM.

Hubbs, C.L. 1929. Studies of the fishes of the order Cyprinodontes, VIII. Gambusia gaigei, a new species from the Rio Grande. Occasional Papers of the Museum of , University of Michigan 198.

Hubbs, C. and V.G. Springer. 1957. A revision of the Gambusia nobilis species group, with descriptions of three new species, and notes on their variation, ecology and evolution. Texas J. of Sci. 9:297-327.

Hughes, J.M. 2015. Yellow-billed Cuckoo (Coccyzus americanus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/418

Ms. Cindy Ott-Jones Page 26

Jameson, J. 2010. Big Bend National Park, Handbook of Texas Online (http//tshaonline.org/handbook/online/articles/gkb02). Accessed September 21, 2015. Published by the Texas State Historical Association.

Meffe G.K, and F.F. Snelson, Jr. 1989. An ecological overview of poeciliid fishes. Savannah River Ecology Laboratory and Department of Biological Sciences, University of Central Florida, Orlando.

National Park Service. 2005. Big Bend National Park Texas Wildland Fire Management Plan. June.

National Park Service. 2015. Biological assessment for exotic species management plans – Big Bend National Park. May 8.

Oberholser, H.C. 1974. The bird life of Texas. Ed.: E. Kincaid. University of Texas Press. Austin, TX.

Pomara, L.Y. 2014. Black-capped vireo survey, Big Bend National Park , Texas. Dept. of Forest and Wildlife Ecology, Univ. of Wisconsin-Madison. For National Park Service. Big Bend National Park, TX.

Pomara, L.Y. and E.M. Wood. 2015. Black-capped vireo survey, Big Bend National Park, Texas, 2015. U.S. Forest Service Southern Research Station, Ashville, NC and Cornell Lab of Ornithology, Ithaca, NY. Report for Big Bend National Park (#BIBE-2015-SCI- 0023).

Potter, E.F. 1980. Notes on nesting yellow-billed cuckoos. J. Field Ornithology 51:17-29.

Rees, M.D. 1988. Final listing rules approved for 25 species. Endangered Species Technical Bulletin. Vol. 13. No. 9-10. University of Michigan, Ann Arbor and U.S. Fish and Wildlife Service. Taylor, N.P. 1985. The Echinocereus. A Kew Magazine monograph. Timber Press. Portland, OR. 160 pp.

Texas Parks and Wildlife Department. 2015. An online database of plant and animal distribution by county in Texas for rare, threatened and endangered species [web application]. Austin, Texas. Available: tpwd.texas.gov/gis/rtest/ (Accessed: October 9, 2015).

Ms. Cindy Ott-Jones Page 27

Texas Plant Conservation Conference. 2003. Proceedings from September 17-19. Lady Bird Johnson Wildlife Center, Austin, TX.

U.S. Fish and Wildlife Service. 1988. Determination of threatened status for Echinocereus chisosensis var. chisosensis. Final Rule 53 FR 38,453-38,456.

U.S. Fish and Wildlife Service. 1989a. Bunched cory cactus (Coryphantha ramillosa) Recovery Plan. Albuquerque, NM. 49 pp.

U.S. Fish and Wildlife Service. 1989b. Lloyd’s mariposa cactus ( mariposensis) Recovery Plan. Albuquerque, NM. 47 pp.

U.S. Fish and Wildlife Service. 1991. Black-capped vireo (Vireo atricapillus) Recovery Plan. Albuquerque, NM.

U.S. Fish and Wildlife Service. 1993. Chisos Mountain hedgehog cactus (Echinocereus chisosensis var. chisosensis) Recovery Plan. Albuquerque, NM.

U.S. Fish and Wildlife Service. 2007. Black-capped vireo (Vireo atricapilla), 5-year review: summary and evaluation. Ecological Services Field Office, Arlington, TX.

Weniger, D. 1970. Cacti of the southwest. University of Texas Press. Austin, TX.

Wilkins, N., R.A. Powell, A.A.T. Conkey, and A.G. Snelgrove. 2006. Population status and threat analysis for the black-capped vireo. Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX. For U.S. Fish and Wildlife Service.